Active semiconductor devices, such as laterally diffused metal oxide semiconductor (LDMOS) transistors, are often used in high power analog circuits. For example, an application for LDMOS transistors and other active semiconductor devices is in radio frequency (RF) power amplifiers. High-resistivity silicon (e.g., greater than 1 kohm-cm) substrate is increasingly being used in RF power amplifiers because it reduces substrate RF power loss, thus conferring considerable benefits to the active and passive elements of an RF system. In such RF systems, low loss and high performance is essential. However, unacceptably high drain current leakage and low breakdown voltage conditions have been observed in some active semiconductor device layouts processed on high-resistivity substrates.